And if the first 3 pools want to make an attack?
https://miningpoolstats.stream/ethereumPOW mining also does not provide security for a coin if 3 large pools have a hashrate of more than 50% of the entire network.
Controlling the largest pools is not enough, ypu also need to control 50% of the mining software used. And you need to control it over a long period of time.